Acoustic device



J. D. SEABERT ACOUSTIC DEVICE Feb. 9, 1932.

Filed May 28, 1930 Patented Feb. 9, 1932 UNITED STATES PATENT OFFHQE JOHN D. SEABER'I, OF DAYTON, OHIO, ASSIGNOR TO GENERAL MOTORS RADIO CORPORA- TION, OF DAYTON, OHIO, A CORPORATION OF OHIO ACOUSTIC DEVICE Application filed May 28, 1930. Serial No. 456,498.

This invention relates to a cone type speaker and more particularly to a cone type speaker adapted to be mounted in the roof of a car.

An object of this invention is to provide a speaker that is as shallow as possible without sacrificing the performance of the speaker so that it may be mounted in the minimum amount of space. This has been accomplished by providing a speaker diaphragm so designed as to provide a space for the driver within it.

Further objects and advantages of the present invention will be apparent from the following description, reference bein had to the accompanying drawings wherein a preferred embodiment of one form of the present invention is clearly shown.

In the drawings:

Fig. 1 represents a side elevation of the speaker looking in the direction of the arrow 1 of Fig. 2.

Fig. 2 is a sectional view taken on the line 22 of Fig. 1.

Fig. 3 is another view of the speaker as viewed in the direction of the arrow 3 in Fig. 2.

In the drawings the reference character 10 indicates the tympanum or the diaphragm of a cone speaker. This diaphragm is made preferably from pressed material or the like so as to have substantially the contour of a conical surface 12 joined to a frusto-conical surface 14. The apex of the surface 14 would appear at 16 by extending the elements 15 and 17 until these intersect as shown;

The point 16 being the vertex of the conical surface 14 that lies eccentric to the axes cd of the conic 12. The axes ab of the cone 12 intersect the axes cd of the conical surface 14 so as to form an acute angle a e d.

This arrangement has been made in order to provide a suitable space for the driving mechanism 20 mounted substantially within the confines of the diaphragm 10 on a plurality of brackets 22, supported on the annu luses 24 and 26 that clamp the edge of the diaphragm 10 in position.

In the particular modification disclosed, a step up leverage connecting the center 18 to the driver 20, has been provided which includes the connecting rod 30, attached to the armature 32 and the lever 34 having one end pivotally mounted at 36 and the other end connected to the center 18 by a small bolt 38.

- not explained for the reason that this forms no part of the invention and is well known to those skilled in the art. The line of intersection 10 of the two conics is substantially oval-shaped so as to accommodate the shape of the driving mechanism 20.

While the form of embodiment of the present invention as herein disclosed, constitutes a preferred form, it is to be understood that other forms might be adopted, all coming within the scope of the claims which follow.

What is claimed is as follows:

1. A sound reproducer, comprising an acoustic diaphragm, said diaphragm including a conical shaped section and a frustoconical shaped section, the axes of the two sections intersecting, and a motor for actuating said diaphragm, said motor being substantially housed within said diaphragm so as to form a compact unit.

2. A sound reproducer, comprising an acoustic diaphragm, said diaphragm including a conical shaped section and a frusto-conical shaped section, said sections intersecting in an oval line, and a motor for actuating said diaphragm, said motor being arranged substantially symmetrical with respect to said oval line of intersection so as to form a compact unit.

3. A compact sound reproducer comprising a motor, and an acoustic diaphragm, said diaphragm including intersecting conic sections, the apices of the conic sections being on the same side of a plane formed by the line of intersection formed by said diaphragms, the motor being substantially inclosed within the acoustic diaphragm so that the maximum height of the speaker is reduced.

4. In a sound reproducer, an acoustic diaphragm, said diaphragm including two intersecting conic sections, said sections having intersecting axes so that the line of intersection formed by said conic sections is substantially oval and a driving unit for actuating said diaphragm, said unit being housed under the smaller conic section.

5. In a sound reproducer, an acoustic dia- I phragm, said diaphragm includingtwo conic sections intersecting in a line, the axis of one conio section intersecting the'surfa'c'e of the other conic section at a point not concentric with the vertex of said other conic section,

and a driving unit housed Within said die:

phragm said driving unitbeing located adjacent to said intersecting line so as to form a 'compact unit.

In testimony whereof 1 hereto afliii my signature.

7 JOHN D. SEABERT. 

